Fondant swags and drapes can be quite challenging, whereas a tip 127 ruffle only takes some practice to master.
Your icing is ragged on the edge because it is too stiff. Add a teaspoon of piping gel to ~ 2 cups of icing to combat this. I use piping gel in both royal and buttercream icings to smooth the edges while maintaining a stiff consistency.
Keep doing what you're doing...practicing. I think you're nuts for doing your own wedding cake
but work on it and I'm sure you'll get the hang of it in no time.
Try to avoid doing the ruffle directly in front of you. If you look at your cake like a clock, work on the ruffle in the 8 o'clock position and bring it around to end at 7o'clock (if you're right-handed). It's difficult to correctly pipe the right half of the ruffle if you're piping it on the cake directly in front of you. Remember to keep the back of the bag pointing in the direction in which the ruffle is traveling...the bag/tip should be at a 45 degree angle to the cake, not a 90 degree angle.
I hope that makes sense. It's much easier to see someone do it than try to read how to do it.